A conventional method of manufacturing a semiconductor device using a dummy structure is disclosed in U.S. Pat. No. 6,033,963.
FIGS. 1A and 1B illustrate processes before and after removing a dummy structure in a method of manufacturing a semiconductor device according to the conventional art.
Referring to FIG. 1A, the structure is formed by preparing a silicon substrate 1 having an isolation layer 2, forming a dummy gate oxide layer 3A on the silicon substrate 1, forming a dummy gate electrode 3B on the dummy gate oxide layer 3A, forming a spacer 4 on a sidewall of the dummy gate, forming source and drain regions 5 by injecting impurities into the surface of the silicon substrate 1, forming a selective tungsten layer 6, and forming an insulating layer 7. Here, the dummy gate oxide layer 3A and the dummy gate electrode 3B function as a dummy structure 3.
Referring to FIG. 1B, a hole 8 is formed after the dummy structure 3 is removed from the structure of FIG. 1A, and then a metal gate electrode is formed in the hole 8.
However, this method of forming the dummy structure has a complicated process which deposits two kinds of materials, and the dummy structure formed by the above method is not clearly removed.